The z-spread is a pricing tool which calculates the number of basis points that need to be added to a zero-coupon yield curve to make the bond’s discounted cash flows equal the bond’s present value.

Yields have consistently fallen since the bond was launched, hitting a low of about 2.3 percent in mid-April.

Although domestic riyal-denominated sukuk issuance has risen dramatically this year so far, with a mammoth $4 billion equivalent sale from General Authority for Civil Aviation (GACA), Saudi borrowers are not as active in dollar markets.

But many -- especially investment-grade corporates -- would find substantial demand. In March, Saudi Electricity Co. reportedly received orders in excess of $15 billion for a $1.75 billion sukuk issue.

A strong regional bid as well as significant global Islamic liquidity are likely to support any potential issue from the bank.

Roadshows are due to end on May 11 in London, and will also cover the United Arab Emirates, Kuala Lumpur and Singapore.

Shares were trading 0.5 percent higher at 0920 GMT, and are up 13 percent year to date.